Keys Leaves Alternate 



xxi 



146. Twigs, as well as leaves, becoming spines. p. 149. Ulex. 

 Only the leaves becoming spines. 147. 



147. Spines without leaflet-scars. 148. 

 Spines with leaflet-scars. 149. 



48. Spines unbranched: stems rather fleshy, p. 239. Fouquieria. 



Spines commonly branched. p. 57. Berberis. 



.49. Buds with evident scales. p. 154. Caragana. 



Bud-scales indistinct: tender. p. 141. Parkinsonia. 



L50. Climbing or scrambling. 151. 



Not climbing. 172. 



51. Climbing by tendrils. 152. 

 With aerial roots but no tendrils. 157. 

 Twining or scrambling, without roots or tendrils. 158. 



52. Tendrils on the persistent leaf-base. p. 8. Smilax. 

 Tendrils opposite the leaf-scars. 153. 



53. Tendrils often ending in disks. p. 225. Parthenocissus. 

 Tendrils not enlarged into disks. 154. 



54. Pith continuous. 155. 

 Pith sub-chambered. p. 222. Ampelopsis. 



55. Stems rather fleshy, terete. p. 223. Cissus. 

 Stems firm. 156. 



>6. Bark not flaking: pith not firmer at nodes. 



p. 225. Parthenocissus. 

 Bark flaking and pith firmer at nodes except in one. 



p. 224. Vitis. 

 57. Evergreen: leaves simple, usually angular, p. 258. Hedera. 

 Deciduous. Poisonous. p. 187. Rhus. 



8. Leaf-scars U-shaped or linear. 159. 



Leaf-scars neither U-shaped nor linear. 160. 

 L59. Buds solitary, scaly: stem often prickly. p. 123. Rosa. 

 Buds superposed, pubescent, indistinct, p. 44. Aristolochia. 



160. Some twigs spinescent. 161. 

 Entirely unarmed. 162. 



161. Twigs 5-ridged, pale. p. 335. Lycium. 



Twigs not ribbed. 



p. 46. Bougainvillea. 



